how to make name accept 3 characters and above just like when publishing a listing because if you register with 1 character in name you wont be able to publish a listing because it require 3 characters

@rei
It's not so easy. You can try to add validation to user register page, same as is on item-post.php.

what do you mean by validation?

@rei
yes

you can add this code in item-post.php below   // Code for form validation  like picture

 contactName: {
            required: true,
            minlength: 3
          },


regard

You should add also message related to this condition (it's bellow to this code in theme).

you can add this code in item-post.php below   // Code for form validation  like picture

 contactName: {
            required: true,
            minlength: 3
          },


regard

Do you mean add that to user-register.php ? because what i need is when user register the minimum name they can enter is 3 characters and above

Yes to user register. ContactName should be changed to name of input that should be required.